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  4. CVE 2026 23247 tcp secureseq add back ports to ts offset
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Back to active CVEs
Medium · CVSS 5.5CVE-2026-23247

tcp: secure_seq: add back ports to TS offsetCVE-2026-23247

Answer in brief

CVE-2026-23247 records a Medium severity (CVSS 5.5) vulnerability in tcp: secure_seq: add back ports to TS offset. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Mar 18, 2026Updated Oct 30, 2026Source checked Nov 4, 2026First seen by HOL Jun 19, 2026Material review Oct 30, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 5.5
Exploitation
Not marked as known exploited
Affected software
12 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:4.10.14:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:4.11:-:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:4.11:rc6:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:4.11:rc7:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:4.11:rc8:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Linux/Linuxgeneric>=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <5da5662181ef8a251e3ba564903002c2e87de452 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <eae2f14ab2efccdb7480fae7d42c4b0116ef8805 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <46e5b0d7cf55821527adea471ffe52a5afbd9caf || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <165573e41f2f66ef98940cf65f838b2cb575d9d1 || 443fac9f2618b93cbc5ab068dc594530236b3a23 || >=4.10.14 <4.115da5662181ef8a251e3ba564903002c2e87de452, eae2f14ab2efccdb7480fae7d42c4b0116ef8805, 46e5b0d7cf55821527adea471ffe52a5afbd9caf, 165573e41f2f66ef98940cf65f838b2cb575d9d1, 4.11
Linux/Linuxgeneric4.11Not reported
Linux/Linuxgeneric>=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <e873e8c16b2fb743a381a9e59c108e63512301ec || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <5da5662181ef8a251e3ba564903002c2e87de452 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <eae2f14ab2efccdb7480fae7d42c4b0116ef8805 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <46e5b0d7cf55821527adea471ffe52a5afbd9caf || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <165573e41f2f66ef98940cf65f838b2cb575d9d1 || 443fac9f2618b93cbc5ab068dc594530236b3a23 || >=4.10.14 <4.11e873e8c16b2fb743a381a9e59c108e63512301ec, 5da5662181ef8a251e3ba564903002c2e87de452, eae2f14ab2efccdb7480fae7d42c4b0116ef8805, 46e5b0d7cf55821527adea471ffe52a5afbd9caf, 165573e41f2f66ef98940cf65f838b2cb575d9d1, 4.11
Linux/Linuxgeneric>=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <025f532d8c5cfac77845e50daab7f478b360f2ac || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <e873e8c16b2fb743a381a9e59c108e63512301ec || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <5da5662181ef8a251e3ba564903002c2e87de452 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <eae2f14ab2efccdb7480fae7d42c4b0116ef8805 || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <46e5b0d7cf55821527adea471ffe52a5afbd9caf || >=28ee1b746f493b7c62347d714f58fbf4f70df4f0 <165573e41f2f66ef98940cf65f838b2cb575d9d1 || 443fac9f2618b93cbc5ab068dc594530236b3a23 || >=4.10.14 <4.11025f532d8c5cfac77845e50daab7f478b360f2ac, e873e8c16b2fb743a381a9e59c108e63512301ec, 5da5662181ef8a251e3ba564903002c2e87de452, eae2f14ab2efccdb7480fae7d42c4b0116ef8805, 46e5b0d7cf55821527adea471ffe52a5afbd9caf, 165573e41f2f66ef98940cf65f838b2cb575d9d1, 4.11

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux, Linux/Linux.
  2. 2Review the reported fix. Update Linux/Linux to 5da5662181ef8a251e3ba564903002c2e87de452; Linux/Linux to e873e8c16b2fb743a381a9e59c108e63512301ec; Linux/Linux to 025f532d8c5cfac77845e50daab7f478b360f2ac if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Mar 18, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 30, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Jun 19, 2026

Sources and claim methodology

  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
Upstream source description

In the Linux kernel, the following vulnerability has been resolved: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.

Quoted source text, attributed separately from HOL analysis.

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
NVD-CWE-noinfo
Source
CVE List V5
Source checked
Nov 4, 2026
References
6 linked sources
Open source record